public class HelloWorld {
    public static void main(String[] args) {
//        Box box = new Box();
//        Integer a = box.student.a;
//        System.out.println(a);

        FemalStudent femalStudent = new FemalStudent();
        FemalStudent femalStudent1 = new FemalStudent();
        Integer a = femalStudent.a;
        Integer a1 = femalStudent1.a;
        System.out.println(a);
        System.out.println(a1);
    }
}

class Person extends Object {
    Person() {
        System.out.println(this.getClass() + "--" + this.hashCode() + "--3");
    }
}

class Student extends Person {

    Integer a = 10;

    Student() {
        System.out.println(this.getClass() + "--" + this.hashCode() + "--2");
    }
}

class FemalStudent extends Student {
    FemalStudent() {
        System.out.println(this.getClass() + "--" + this.hashCode() + "--1");
    }
}

class Box {
    Student student;
}
